CircuitBreaker

stygian_graph::ports

Trait CircuitBreaker 

Source 
pub trait CircuitBreaker: Send + Sync {
    // Required methods
    fn state(&self) -> CircuitState;
    fn record_success(&self);
    fn record_failure(&self);
    fn attempt_reset(&self) -> bool;
}
Expand description

Circuit breaker port for resilience

Implements the circuit breaker pattern to prevent cascading failures when external services are unavailable. Uses interior mutability for state management.

§Example Implementation

use stygian_graph::ports::{CircuitBreaker, CircuitState};
use stygian_graph::domain::error::Result;
use parking_lot::RwLock;
use std::sync::Arc;

struct MyCircuitBreaker {
    state: Arc<RwLock<CircuitState>>,
}

impl CircuitBreaker for MyCircuitBreaker {
    fn state(&self) -> CircuitState {
        *self.state.read()
    }

    fn record_success(&self) {
        let mut state = self.state.write();
        *state = CircuitState::Closed;
    }

    fn record_failure(&self) {
        let mut state = self.state.write();
        *state = CircuitState::Open;
    }

    fn attempt_reset(&self) -> bool {
        let mut state = self.state.write();
        if matches!(*state, CircuitState::Open) {
            *state = CircuitState::HalfOpen;
            true
        } else {
            false
        }
    }
}

Required Methods§

Source

fn state(&self) -> CircuitState

Get current circuit breaker state

§Returns

Current state (Closed, Open, or HalfOpen)

§Example
match cb.state() {
    CircuitState::Closed => println!("Normal operation"),
    CircuitState::Open => println!("Circuit is open, failing fast"),
    CircuitState::HalfOpen => println!("Testing recovery"),
}
Source

fn record_success(&self)

Record successful operation

Transitions HalfOpen -> Closed, maintains Closed state.

§Example
// After successful API call
cb.record_success();
Source

fn record_failure(&self)

Record failed operation

May transition Closed -> Open or HalfOpen -> Open depending on failure threshold configuration.

§Example
// After failed API call
cb.record_failure();
Source

fn attempt_reset(&self) -> bool

Attempt to reset circuit from Open to HalfOpen

Called after timeout period to test if service recovered.

§Returns
  • true - Successfully transitioned to HalfOpen
  • false - Already in Closed or HalfOpen state
§Example
if cb.attempt_reset() {
    println!("Circuit breaker now in HalfOpen state");
}

Implementors§